Many sports bras are designed to limit or prevent movement of a wearer's breasts while she is engaged in athletic activity. During high impact activities, a woman's breasts do not move up and down together, but rather separately, in what can be called a “butterfly” motion. This movement of the breasts is very painful and possibly damaging to the supportive breast tissue. Currently, the common ways of supporting the breasts during athletic activity and controlling this butterfly motion are by high compression fabric, components, and construction; rigid fabric and components; and/or encapsulation of the breasts via separate breast cups, usually requiring a molded pad with or without an underwire, and usually requiring two individual cups that surround each breast, keeping, them separate.
Constructing a garment using the above-mentioned material and methods results in a tight and uncomfortable fit for the wearer; however, women who require a supportive garment to reduce breast movement during high impact exercise have no choice but to wear a similarly-constructed garment or multiple support garments to meet their breast support needs. For more information regarding breast discomfort during physical activity, and the detrimental effects thereof, please see An Abstract of the Thesis “Breast Support for the Active Woman: Relationship to 3D Kinematics of Running,” by Ann L. C. Boschma, submitted to Oregon State University on Sep. 23, 1994. Boschma summarizes her study of running kinematics with the following observation: while exercising, women of all breast sizes experience increases in breast discomfort as breast support decreases. This indicates that full support bras are more comfortable for a wearer engaged in vigorous athletic activities, no matter what her breast size.